A window well attaches to your home’s foundation near ground-level or below-grade windows to prevent flooding, add natural light, and act as an emergency exit. If you have the right tools and physical strength, you can replace or install a window well in a few hours. Learn more about window well installation and how to make sure your project is up to code.
Prepping to Install a Window Well
Before you get out your shovel, you’ll want a few things in place, including your window well insert.
Measure Your Window
If you have an existing window well that you’re replacing, remove it and measure its height, width, and depth. If you don’t have a current window well, measure the height and width of your window with a tape measure.
Add at least 8 inches to the height and 6 inches to the width to ensure that the window well fits around the outside of the window. For example, if you have a window that’s 24 inches wide by 36 inches tall, your well should be at least 30 inches wide by 44 inches tall.
Buy a Prefabricated Well
Purchase a window well from a home improvement or hardware store that matches the size you need. You can find plastic, steel, fiberglass, and concrete window wells that come in various colors, designs, and sizes. Many of them are semi-circular or square. The cost of the window well depends on the material and size.
Call 811 Dig
Before you dig, ensure there are no buried utility lines or cables near the area. Call or contact 811 online a few business days before starting your project. They’ll send workers to your home to mark your utilities.
Ask for Help
If the window well is too heavy to lift on your own, ask a neighbor or friend to assist you during parts of the project. A little help can go a long way with this project!
With a shovel (or some heavy-duty equipment if you happen to have access to it and are licensed to use it), dig a hole 6 inches wider than your window and 8 inches deeper than the bottom of the window sill. Shovel the dirt into a wheelbarrow for easy transport. You’ll use some of the dirt to backfill the hole, so don’t cart it all away just yet.
Test the Positioning
To ensure you have a hole that’s deep and wide enough for your window well, set the insert inside the hole. The bottom of the well should be at least 8 inches below the base of the window. The window well should also be 3 inches higher than the surface-grade ground. If the well doesn’t fit those parameters, adjust the depth and size of your hole.
Drill the Drain Holes
Use an auger or shovel to dig a straight 4- to 5-inch-wide hole in the bottom of your window well opening. The drain hole should be in the center of your window well. Dig a straight path down until you reach the layer of gravel under your home.
Place Your Drain Tube
Put a perforated drain tube with a drain cap in the drain hole. The cap prevents dirt and gravel from entering the tube and clogging it.
Backfill the Drain Hole
With the drain tube in the center of the drain hole, pour gravel around the tube to hold it in place. Pack the gravel into the hole until the gravel is flush and level with the drain cap.
Insert your window well and push it against the foundation so it’s flush with the foundation wall. Make sure the insert is centered on your window, then ensure that the well is level. Make adjustments by adding dirt or gravel underneath until the well insert is level. Keep in mind that the top of the window well should be at least 3 inches higher than the surface-grade ground.
Predrill Your Foundation Holes
With the window well flush against your home, use a marker to indicate where on your foundation you will drill the holes to anchor the window well. The window well shouldn’t shift when marking the holes, as any changes could alter how level the well is or how it aligns with the pilot holes.
Take out the window well and drill 2-inch-deep pilot holes into the foundation with a masonry bit. Use a 3/8-inch masonry bit and hammer drill to create pilot holes in your foundation. Always wear safety glasses and a dust mask when drilling into a foundation.
Screw Anchors Into Foundation
Photo: ungvar / Adobe Stock
Set your window well back in place. Screw the window well into the predrilled holes with masonry anchors and a hammer drill. Secure the anchors with nuts using a socket wrench.
Caulk the Seam
Caulk the sides of the well where it meets the foundation to prevent leaks. Use a silicone sealant and a caulk gun.
Add Gravel to the Well
Photo: Ozgur Coskun / Adobe Stock
Add 3 inches of gravel or drainage rock to the bottom of the well. The gravel layer inside the window well should be lower than the window sill to prevent water from seeping into the window.
Next, fill the space outside the window well with gravel, then add dirt as the outside layer. Pack down the gravel and dirt with a shovel.
Install a Window Well Cover
You may choose to add a window well cover to the top of your window well. A cover can help prevent dirt, water, and animals from entering the window well. You can permanently affix your cover or allow it to be removable.
DIY vs. Hiring a Pro
You can install a window well with the right tools, time, and physical strength. Follow depth, width, and installation guidelines to ensure water doesn’t leak through the window.
If you’re installing a window well and adding an egress or another type of window to your basement, you may want to consider hiring a local window pro. The project requires specialized skills, knowledge, and carpentry experience. It also requires digging and grading the ground.
The cost for window well installation can run from $500 to $1,500. The average cost of an egress window falls around $3,900, including installation. Window replacement costs range from $100 to $750 per window. All of this goes to say that this isn’t a project you want to DIY just to make a small mistake and have to pay (a lot) to fix it.
Who Can Install Window Wells?
Beyond a local window installer, a few other pros can handle the job:
General contractor: A general contractor runs an entire project and hires out subcontractors for specialty work. A general contractor can tackle window well installation as a part of a more extensive remodel, such as finishing your basement. General contractors typically charge 10% to 20% of the total project price.
Landscaper: If you need to excavate and level the land to make space for your window, you might hire a professional landscaper. Landscapers typically charge between $8 and $25 per cubic foot for dirt removal, with hourly rates for more involved work, like grading, averaging between $50 and $200 per hour.
Foundation contractor: Installing a window well and below-grade windows typically requires risky cutting and drilling work on your home’s foundation. Consult with a local foundation contractor to ensure you avoid any mistakes that could threaten the stability of your home. The cost of foundation work typically runs about $200 per hour.
Frequently Asked Questions
Installing a window well costs anywhere from $500 to $1,500 or more. Adding an egress window and well runs about $3,900 on average. Adding a window well cover to the project can add $200 to $700. A well cover helps protect your egress windows from weather damage and keeps them clear of dirt, debris, and wildlife.
Yes. Window wells should have drains to let water flow away from the window. If a window well doesn't have a drain, it could lead to a basement seepage problem, costly water damage, and potential mold growth. Window well drains can connect to either an interior or exterior drain tile. You can dig the drain yourself with a shovel or auger or hire a window installer to handle it for you.
The proper way to install a window well is to measure the window, dig a hole deeper and wider than the window, place a drainage tube and cap, anchor the well to the foundation, caulk the seam, and backfill the hole. The job requires tools such as a hammer drill and auger and some heavy digging. Proper placement and window well installation are critical to preventing water from leaking into the window.
You install a window well 8 to 12 inches deeper than the base of the window sill. After filling the well with drainage rock, the well should sit 3 inches below the bottom of the window. The top of the window well should also be at least 3 inches higher than the surface-grade ground. The window well should be about 6 inches wider than the window opening.
Yes, you need to attach a window well to the foundation to ensure it doesn’t become loose, shift, or cause leaks near your home’s foundation. Use a hammer drill and masonry bit to drill into your home’s foundation. After you drill pilot holes, secure the window well with masonry anchors, ensuring that the well stays flush with the foundation and level with the ground.
